The use of plastic glazing is well known, for example in the automotive industry they may be used for windows, headlamps, and tail lights. In the process of manufacturing such plastic glazing, a plastic substrate generally is coated with a weatherable layer which is optionally over-coated via the deposition of an abrasion resistant layer. This abrasion resistant layer may be a plasma coating which is generally deposited in deposition chamber at sub-atmospheric pressure.
In the manufacture of plastic glazing, it may be desirable to mold the plastic substrate with tabs to facilitate the handling of the glazing during the manufacturing process. The plastic glazing may also have gates, associated with the molding process, along the edge of the molded plastic. These tabs or gates are typically removed from the glazing before its final use. If the glazing is thermoformed rather than molded there maybe excess plastic at the perimeter that would generally be removed after a plasma coating is applied. After removing the tabs, gates or excess plastic, an edge is left which is not coated with a weatherable layer or a plasma coating. The current common practice is to leave the edge uncoated or treat the edge by wet coating. The absence of coating or the presence of wet coating on the edge can cause problems with the application of subsequently applied adhesive or encapsulation because the uncoated plastic or the wet coat is different from the rest of the glazing. Practical and feasible processes for local plasma coating are needed to address these problems.
Another problem that may be encountered with plastic glazing is that during their use, for example as windows in an automobile, the plasma coating layer may be chipped. The resulting surface damage is undesirable because it exposes that portion of the glazing to the environment. Because of the time and cost involved in replacing the entire window, it would be desirable to repair the window while it remains in place. However, currently there is no practical process for doing so. Thus, practical processes are needed for repairing a window while in place.